And so for all I know, his eventual abduction by a ghost may be Don Giovanni's latest invention, staged by himself to get rid of all these former victims who are now running after him and spoiling his fun. His being taken to hell by the animated statue of the commander through a gaping hole in the ground alit with huge flames is timed just so that these pursuers can witness it through a window. Then, whereas in the front of the stage his irate victims turned chasers sing his demise in their final moralizing Questo è il fin, I see a trapdoor opening in the floor in the back of the stage. Out of it climbs the actor who played the statue of the commander, now quite limber rather than slow as a rigid statue; soon he's helping Don Giovanni himself out of the basement. As the actor starts removing the make up and the costume of the commander, Don Giovanni takes out his purse and pays him in gold. When he is done, the actor salutes and leaves, and Don Giovanni makes a sign to Leporello to continue with the plan: keeping the idiots busy singing and believing, while he gallops to the next city where Leporello will join him later. Before he goes, Don Giovanni dons the long clothes of a monk, complete with a hood hiding his face. One last time, he makes obscene gestures at his victims, to silently mock their superstition. His evil adventures may very well be headed to an inevitably violent conclusion, it's just not going to come from this particular gullible lot. He then walks victoriously to the door, composes himself into the character of a travelling monk, and leaves the stage incognito.
At least, that's how things would turn out if I had a say in a production of Mozart's masterpiece. It would certainly bother me quite a bit to let the scoundrel literally get away with murder scot-free; but after all unhappy endings are par for the course in Opera.